Q. A small object with a mass of 400 mg carries a charge of 35.0 nC and is suspended by a thread between the vertical plates of a parallel-plate capacitor. The plates are separated by 6.00 cm. If the thread makes an angle of 17.0° with the vertical, what is the potential difference between the plates?
Q. A 21.3-kg child is on a swing attached to ropes that are L = 1.55 m long. Take the zero of the gravitational potential energy to be at the position of the child when the ropes are horizontal.